Dynamic speed display signs are being used in many jurisdictions across Canada. The devices display the speed of passing vehicles, typically along with a sign showing the posted speed limit. Intended to increase driver awareness of speed limits and to provide instant feedback to motorists by displaying the actual speed being travelled, the devices have been found to be effective shortly following installation. The Application Guidelines for Speed Display Devices were developed to establish best practices and guidance for speed display devices design and application in the Canadian context for a variety of uses. The Guidelines enable and encourage uniformity in application of devices throughout Canada, and are intended to be a complementary detailed reference document, for use in conjunction with the Manual of Uniform Traffic Control Devices for Canada (MUTCDC).
Au cours des dernières années, une prolifération de carrefours giratoires a été observée partout au Canada. À ce jour, il n’existe aucune source unique traitant de la conception, de la construction, du fonctionnement et de l’entretien des carrefours giratoires à l’intention des professionnels canadiens. Chaque région du pays a choisi de s’inspirer de différentes sources, y compris des lignes directrices d’autres pays. Le Guide canadien de conception de carrefours giratoires a pour objet de fournir des renseignements et des conseils sur la planification, la conception, la construction, le fonctionnement, l’entretien et la sécurité des carrefours giratoires au Canada. Le guide sert de document d’accompagnement au Guide canadien de conception géométrique des routes de l’Association des transports du Canada et fournit des directives spécifiques à l’utilisation et à la conception de carrefours giratoires.
This case history reviews geotechnical conditions and design of the North Commuter Parkway (NCP) roadways and bridge crossing of the South Saskatchewan River at Saskatoon SK. The geotechnical investigation of the NCP crossing identified complex geotechnical conditions in both the river valley and on the upland. The site was located within the ancestral Glacial Lake Saskatchewan, a proglacial lake that deposited variable depths of interbedded silt, sand and highly plastic clay. Development of the river channel had eroded much of the lacustrine sediments and underlying till leaving an eroded till landform with clay remnants on one side of the valley and lacustrine sediments on the other. This varying morphology presented highly variable geotechnical conditions with significant design challenges. Groundwater conditions were controlled by regional aquifers that underlay the entire project area in addition to local unconfined aquifers that were also addressed. This paper presents the geotechnical design issues that were encountered in constructing the roadways and valley crossing. It addresses geotechnical conditions, foundation design, materials selection, groundwater control and construction issues that were addressed to successfully deliver this P3 project that is scheduled for completion in 2018.
In 2013, the City of New Westminster conducted a Downtown parking study which demonstrated that half of the parking (approx. 400 stalls) provided by the Front Street Parkade could be removed due to reduced parking demand. Subsequently, half of the Parkade was removed in 2015 and the Frontage Road, adjacent to Front Street, was redeveloped as a “Mews”- a narrow, intimate street that balances the access and service functions of a lane with active building frontages, accessory uses, and a street space shared by cars, bicycles and pedestrians. Unlike typical car-oriented streets, the Mews is a comfortable and safe place for everyone – pedestrians, cyclists and drivers- that was conceived through extensive consultation and a multi-disciplinary approach to its planning and design. The contemporary design for the mews transforms car-oriented infrastructure into a place for people with a continuous plaza-like paving pattern, social seating areas, lighting, street trees, traffic calming, public art and 35 back-in angled parking stalls to access local businesses. The fully accessible, one-way street is designed for day-to-day social and retail activity as well as for temporary closures to host special events and community festivals.
Cement stabilized subgrades have been extensively used to improve the engineering performance of pavement structures. Due to the effects of cementitious hydration, pozzolanic reaction, as well as, cation exchange, chemical bonding is generated between fine soil particles. Therefore, the geotechnical characteristics of difficult clay soils will be improved in terms of plasticity, strength, stiffness, and durability. The cement modified soils (CMS) will then function as a new pavement layer which partially or totally preplaces the thickness of granular base layer as commonly found in traditional road constructions. This paper first introduced a subgrade stabilization project located in Chatham-Kent, Ontario, followed by the field testing of subgrade stiffness using a light weight deflectometer (LWD) test on the stabilized subgrade surface. Five different low-volume roads were chosen as test sections for LWD stiffness test. The stiffness of the subgrades was measured before the construction, 3 hours after the stabilization followed by testing at 3 days, 7 days, 28 days, and 1 year respectively. Field test results indicated a significant increase of the subgrade stiffness after the cement stabilization and compaction; moreover, the stiffness continued growing along with the curing time. Soil sampled from one of the test sections was tested in lab facilities. Laboratory testing including: unconfined compressive strength (UCS) at 7 days and 28 days, durability test and pH values test for cement stabilized soil. Stabilized soil had 7 days UCS value of 0.83 MPa with 6% cement, and 1.43 MPa with 12% cement. Moreover, 5% to 6% cement stabilized T38 soil specimens had improved durability properties against freezing and thawing and met the weight loss limit requirements. Results also indicated that the cement stabilization changed the soil environment from slightly acidic to alkaline, and reduced the potential for growing of organics. It is also recommended future studies evaluate mixes with supplementary cementing materials to provide a more environmentally friendly stabilized subgrade. The paper finally introduces alternative Hydraulic road binders (HRB) as a more economic, sustainable and environmentally friendly solution to the construction and rehabilitation of Canada’s low-volume roads.
The Ontario Ministry of Transportation (MTO) manages provincial structures in Ontario including 2850 bridges. Following an extended period of fiscal restraint, the last decade has marked a dramatic increase in bridge construction work, with rehabilitation of a third of the provincial bridge inventory. Bridge design and corrosion protection have evolved over the last 60 years. The practice of bridge rehabilitation is well-established in Ontario. Through the 1990s, standards were introduced for integral abutments, semi-integral abutments, and flexible links slabs between simply-supported spans to improve a bridge’s durability in initial construction or rehabilitation. Accelerating bridge construction by reducing time on site is a current focus. The MTO has tried many forms of prefabrication.
The use of Reclaimed Asphalt Pavement (RAP) in Hot Mix Asphalt (HMA) production is consistent with the concept of sustainability and when designed and constructed properly, it can potentially provide a more cost-effective alternative to conventional road practices. However, RAP is suspected to have negative effects on thermal cracking resistance of Hot Mix Asphalt mixes. The extent of blending between aged binder and virgin binder in asphalt mixtures could affect both the performance of the produced HMA and the economic competitiveness of the recycling process. During the production process of HMA with RAP, it is generally understood that a partial blending occurs between aged and virgin binders. Yet, a limited number of studies have considered the time-temperature effects of the silo storage on the performance of HMA RAP mixes. In this study, the effect of silo storage time on mitigation of thermal cracking of the HMA containing RAP is examined. HMA samples of HL-3 and HL-8 mixes, designed with 15% and 30% RAP respectively, were collected after production from the asphalt plant at different silo-storage intervals (1, 4, 8, and 12 hours), with their temperature being closely monitored and recorded. The thermal cracking resistance of the resulting mixes were characterised using Thermal Stress Restrained Specimen Test (TSRST). Results indicate that the samples collected after 8 and 12 hours of silo storage exhibited an improvement in the thermal cracking resistance accompanied with a reduction in their corresponding stiffness compared to those collected at 0 hours. These results indicate that silo storage would then improve the blending between aged and virgin binders and improve the low temperature behaviour of the asphalt mix.
Geotechnical-related structures such as pavements have been widely used in cold-weather regions like most part of Canada. Due to the effect of global warming, pavements in cold regions will be thaw earlier and the number of freeze-thaw cycles are increasing each year. In addition to typical design considerations at normal temperatures, a pavement design must also take into account the unique issues related to freeze-thaw cycles, such as degradation of material properties. In this regard, Geosynthetics have been employed in cold regions to stabilize pavement system during construction and mitigate potential problems during their service at low temperature. This paper starts with the evaluation of the effect of environmental freeze-thaw (F-T) condition on the mechanical behavior of the base asphalt mix (GB20) according to the specifications of the MTQ in the LCMB (Le Laboratoire sur les chaussées et matériaux bitumineux) laboratory at the École de Technologie Supérieure (ÉTS) and further discusses past studies and their key findings on the application of geosynthetics to enhance the performance pavements in cold regions. The results reveal that geosynthetics at low temperature shows higher tensile strength and stiffness and reduced elongation before failure which can considerably upgrade the pavement behaviour in cold regions.
The authors of the original 2015 CTAA manuscript “Physical Hardening in Asphalt” wish to acknowledge the response paper submitted by Mr. Alexander (Sandy) Brown. We wish to thank Mr. Brown for his extensive analysis of the weather data surrounding the early 2014 and 2015 cracking incidents in the Battersea Road, Kingston contract of 2009. As the lead author of the original manuscript, and the person who prepared the Battersea Road case study for the 2015 Ottawa podium presentation, I wish to provide this Author’s Closure in response to the discussion prepared by Mr. Brown. I disagree with his conclusion that it would have been better to specify a regular PG -34 grade for the Battersea Road reconstruction. The LS-299 Double-Edge-Notched Tension (DENT) and LS-308 Extended Bending Beam Rheometer (ExBBR) tests and associated acceptance criteria will soon be used by a majority of user agencies in Ontario, and are gaining attention in the rest of Canada and abroad for their precision and results.
Rather than a commentary on the paper presented in the 2015 CTAA proceedings, this is a commentary on the presentation given at the 2015 conference, which presented information not included in the paper. The authors presented information regarding a case study on cracking to an 8-year-old pavement on Battersea Road in Kingston, Ontario. The presentation was critical of the performance of the asphalt cement that met to new specifications developed by the paper’s authors and Queen’s University. The case study presented indicated that while the asphalt cement met all the testing procedures outlined in the contract documents it still cracked in 5 years. The specified asphalt cement grade on the contract was a PG 58-28 meeting Extended Bending Beam Rheometer (ExBBR) and Double Edge Notched Tension (DENT) criteria. The issue that needs to be addressed is the specification of a PG xx-28 for pavements in Kingston, Ontario.
The original paper examined initial cracking performance of various pavement sections and evaluated the relationship between field cracking and test results for Extended Bending Beam Rheometer (ExBBR), Double Edge Notched Tension (DENT) test, and Multiple Stress Creep Recovery (MSCR). Some of te pavement sections were constructed as test sections with construction and material variables closely accounted for, while others such as the 2007 investigation and 2011 asphalt cement initiatives were not. Where not constructed as a controlled test section, results can always be debated. However, the overarching observation from all studies was that the poor quality of the asphalt cement was one of the main contributing factors to premature pavement cracking and that implementation of an enhanced specification was necessary. The ultimate goal remains to move towards a performance specification addressing cracking and overall durability. The authors of the original paper would like to acknowledge the commentary by Mr. Sandy Brown, Consulting Engineer in Toronto, Ontario. It is believed that the topic is important and such technical discussions are necessary to better understand the effect of asphalt cement quality on the performance of asphalt pavements. This paper provides our response to the comments in the same order as the commentary paper.
Premature pavement cracking is a type of distress that has been gaining increasing attention in recent years. Much of MTO’s research into the distress has been focused on the quality of the asphalt cement. While this author agrees that the specifications for asphalt cement in Ontario need to be improved, the issues are much broader than just the asphalt cement. Nonetheless, MTO’s paper presents much of the background for their development of two new test procedures: the Extended Bending Beam Rheometer (ExBBR) test and the Double Edge Notched Tension (DENT). These tests were developed to address premature pavement cracking in Ontario. However, an examination of the data presented in the paper in support of the new specifications indicates that the conclusion may not be as certain as portrayed.
A GIS is classically defined as a system that inputs, stores, processes, analyses, and outputs geographic data. Advancements in processing tools and computing power have not changed the fundamental definition. This poster demonstrates how these elements of GIS, represented by the GIS Lifecycle Loop, can be used to analyze road LiDAR data for roadway settlement detection and asset identification.
In recent years, the Ministry of Transportation of Ontario (MTO) has identified a need for a rehabilitation method that: a) has a long service life, b) can be installed in 8-hour construction windows, and c) can be installed reliably. Because of good success in past, PRECAST CONCRETE PANELS were identified as a promising option. Support conditions beneath panels are typically considered to be one of the primary considerations for a well-performing precast slab. During detailed design, three different designs differentiated by their support conditions were produced. A test section was constructed in September 2016 which incorporated each of the three designs. This study considers and evaluates the support conditions based on their construction, including input from the MTO and Dufferin Construction, who constructed the test section.
Although Superpave provides pavement engineers with a method of selecting materials and designing for better performance, the prediction and evaluation of its performance is not integrated in agency pavement management systems (PMS). There is a need to investigate the realistic prediction of the performance of Superpave and how it is used in the pavement management system. The main objective of this research was to compare the distresses predicted by the Mechanistic -Empirical (M-E) approach to the field evaluated performance and Laboratory performance tests.
This study looks at the initial surface texture of three PCC pavements constructed in summer/fall of 2016 and compares with skid-resistance performance as measured by the British Pendulum Test (BPT).
Residential streets within the City of Hamilton have composite pavements that require a rehabilitation solution. Composite pavements are usually maintained using a mill-and-replace strategy, however, due to joints in the underlying concrete pavement, reflective cracking through the asphalt is very common. Objectives of this study included assessing the feasibility of concrete overlays as a resurfacing/maintenance strategy for the City of Hamilton to use on its municipal streets; developing a construction/implementation guideline for municipalities; and measuring key aspects such as construction cost, construction challenges, pavement durability, and required maintenance cost and frequency.
More than 25 design methods exist for jointed plain concrete pavements (JPCPs) --Many are based on the 1950s AASHO Road Test, including AASHTO 93 and CHAUSEE2 --The prominence of these methods created an expectation for JPCP thicknesses Modern JPCP design methods in North American are: --Founded in mechanistic (M) principles such as finite element analyses and; --Supplemented with empirical (E) calibration to field performance to increase the accuracy of key performance predictions of importance to owners and users, such as: Cracking in slabs, Faulting in joints, and International Roughness Index (IRI). This study extends prior work that compared AASHTO 93, Pavement ME, and StreetPave to illustrate the breadth of design variables considered and the sensitivity of required JPCP thickness to traffic magnitude, the use of dowels, concrete flexural strength, concrete modulus of elasticity, edge support, design reliability, and k-value
Stage 1 of the Southwest Transitway, the initial phase of the City of Winnipeg’s rapid transit network, opened for service in April 2012 providing fast, frequent, reliable service without transfer for most passengers travelling between the southwest part of the City and downtown. The City’s next rapid transit project, Stage 2 of the Southwest Transitway, will extend the transitway southerly to the University of Manitoba. The Southwest Rapid Transitway (Stage 2) and Pembina Highway Underpass Project (SWT2) includes the construction of 7.6 km of exclusive transitway runningway and active transportation paths; six transitway and three rail structures; a noise attenuation wall; two land drainage pump stations; eight rapid transit stations; park and ride facilities; extensive utility and rail relocation works; and reconstruction and widening of the Pembina Highway Underpass. Advancing SWT2 from functional design to construction required the collaboration of engineering specialists, procurement lawyers, and financial advisors. This paper focuses on the engineering aspect of 1) the preparation of the business case and value for money assessment (VFM) for a PPP Canada funding application; 2) preparation and evaluation of the request for qualification (RFQ); 3) preparation and evaluation of the Request for Proposal (RFP), and 4) finalization of the project agreement (PA) for SWT2. The business case and VFM assessment compared a Design, Build, Finance, (operate), and Maintain (P3) procurement against a traditional Design-Bid-Build approach. The engineering aspect for this process included preparation of detailed capital cost estimates. Due to the nature of SWT2, PPP Canada’s Schematic Estimate Guide was not directly applicable (typically used for vertical infrastructure) so a modified costing format was developed. Following confirmation of the P3 procurement method and project funding, an RFQ was issued that prequalified three Proponents. The RFP issued to the Proponents was separated into two main parts: 1) RFP (bidding instructions); and 2) PA (project contract) that detailed the terms of the project delivery. Engineering services provided during the RFP open period included Proponent requests for information, participation in commercially confidential design meetings, modifying the PA to facilitate Proponent innovations, and assistance in the evaluation of technical submissions. The Government of Canada is contributing up to $91.2 million through the PPP Canada Fund while the Province of Manitoba and City of Winnipeg will contribute the balance of the Project costs. At a cost estimate of $467.3 million, this is the largest infrastructure investment undertaken by the City of Winnipeg to date.
High Occupancy Toll (HOT) lanes are considered as one of the traffic management strategies to efficiently utilize the available roadway capacity. In order to understand drivers’ reactions to the planned HOT lane along the Highway 427 corridor in the City of Toronto and estimate the value of time (VOT) and value of reliability (VOR), a web-based stated preference survey was carefully designed and conducted. Using Multinomial Logit (MNL) and Nested Logit (NL) models, the travellers’ willingness-to-pay was derived as the trade-off between travel time saved and toll incurred. The models were further estimated for different market segments.